Sounds like you have what is called an adjacency list with people/houses and you may be able to resolve this with a recursive CTE (or perhaps not).
Two questions:
1. Do you need to stop at step 4 or resolve all the way through to the end?
2. What happens when the same house ID comes up for more than one person? In other words, do you need to ignore duplications on each additional resolution step?
If the answer is Yes to ignoring duplicates, you may need to do this with a set-based loop.
My thought question: Have you ever been told that your query runs too fast?
My advice:
INDEXing a poor-performing query is like putting sugar on cat food. Yeah, it probably tastes better but are you sure you want to eat it?
The path of least resistance can be a slippery slope. Take care that fixing your fixes of fixes doesn't snowball and end up costing you more than fixing the root cause would have in the first place.
Need to UNPIVOT? Why not CROSS APPLY VALUES instead?[/url]
Since random numbers are too important to be left to chance, let's generate some![/url]
Learn to understand recursive CTEs by example.[/url]
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